Fix nits in the lexical analysis section: \u requires four digits, backtick is not allowed in source in 3.x.
Fix nits in the lexical analysis section: \u requires four digits, backtick is not allowed in source in 3.x.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator